CMOS current-mode exponential-control variable-gainamplifier

Abstract

A CMOS current-mode exponential-control variable-gain amplifier is presented. It consists of a first-order current-mode pseudo-exponential circuit and a current-mode multiplier. Based on the Taylor's series expansion, the pseudo-exponential circuit can be realised by MOSFETs in saturation. The proposed circuit has been fabricated in a 0.5 µm N-well CMOS process with a gain control range of 15 dB. The experimental results confirm the feasibility of the proposed variable-gain amplifier.